Briquette for lowering the viscosity of metallurgical slag and process for its production

Abstract

Briquettes for the liquefaction of metallurgical slag are formed from a mixture containing, by weight, 85-98% slag from secondary aluminium processing, 1 to 8% polyvinyl acetate dispersion as the polymeric bonding agent and the remainder water, the briquettes containing water in the form of residue humidity at a quantity of maximally 1.5%, ideally no more than 0.5%, in relation to the overall weight of the briquettes, and the briquettes have a specific weight of 1,500-5,000 kg.m −3 and a compression strength of at least 20 MPa. Ideally, the mixture contains 90-92% slag from secondary aluminium processing, 1 to 3% polyvinyl acetate dispersion and the remainder water. The mixture may also contain 0.5-2% unsaturated acid, selected from the group containing oleic acid and/or palmitic acid and/or stearic acid, as a hydrophobic ingredient. The ideal shape of the briquettes is cylindrical.

What is claimed is:  
     
       1. Briquettes for the liquefaction of metallurgical slag, formed from a mixture comprising, by weight, 85-98% slag from secondary aluminium processing, 1-8% polyvinyl acetate dispersion as a polymeric bonding agent, and remainder of water; the briquettes containing water in the form of residue humidity in a quantity of up to 1.5% by weight in relation to the overall weight of the briquettes, wherein the briquettes have has a specific weight of 1,500-5,000 kg.m −3  and a compression strength of at least 20 MPa. 
     
     
       2. Briquettes according to  claim 1 , containing residue humidity in an amount of up to 0.5% by weight in relation to the overall weight of the briquettes. 
     
     
       3. Briquettes according to  claim 1 , wherein the mixture contains, by weight, 90-92% slag from secondary aluminium processing, 1-3% polyvinyl acetate dispersion and remainder of water. 
     
     
       4. Briquettes according to  claim 1 , wherein the mixture also contains, by weight, 0.5-2% unsaturated acid, selected from the group consisting of oleic acid, palmitic acid and stearic acid, as a hydrophobic ingredient. 
     
     
       5. Briquettes according to  claim 1 , wherein said briquettes are cylindrical in shape. 
     
     
       6. Method of manufacture of briquettes according to  claim 1 , comprising the steps of mixing slag from secondary aluminium processing, polyvinyl acetate dispersion as bonding agent and water for a period of 10-60 seconds to form a homogenous mixture; pressing the homogenous mixture at a specific press power of 110 to 130 MPa to form briquettes; drying the briquettes at a temperature between 120 and 200° C. for a period of 30-60 minutes, depending on the weight of the briquettes, until the amount of residue water is reduced to a maximum value of 1.5% by weight, and after drying, cooling the hot briquettes, and wrapping the cooled briquettes for protection against humidification. 
     
     
       7. Method according to  claim 6 , including a step of preheating the mixture to a temperature of 25 to 90° C. prior to mixing the components into a homogenous state in the mixer. 
     
     
       8. Method according to  claim 6 , wherein after drying and prior to wrapping, cooling the hot briquettes to 30-50° C.